Declaration of Pillnitz

The Declaration of Pillnitz occurred on 27 August 1791 at Pillnitz Castle in Saxony, Germany, where King Friedrich Wilhelm II of Prussia and King Leopold II of Austria declared the joint support of Austria and Prussia for King Louis XVI of France against the French Revolution. The National Assembly of the French First Republic interpreted it as a promise of invasion, leading to France declaring war on Austria and Prussia on 20 April 1792.